h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 131

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

Bit
13
12
11
10
9
8
7
6
Bit Name
RCW1
RCW0

RTCK2
RTCK1
RTCK0
RFSHE

0
Initial
Value
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
CAS-RAS Wait Control
These bits select the number of wait cycles to be
inserted between the CAS assert cycle and RAS assert
cycle in a DRAM refresh cycle.
00: Wait state not inserted
01: 1 wait state inserted
10: 2 wait states inserted
11: 3 wait states inserted
Reserved
Refresh Control
Reserved
Description
This bit can be read from or written to. However, the
write value should always be 0.
Refresh Counter Clock Select
These bits select the clock to be used to increment the
refresh counter. When the input clock is selected with
bits RTCK2 to RTCK0, the refresh counter begins
counting up.
000: Count operation halted
001: Count on φ/2
010: Count on φ/8
011: Count on φ/32
100: Count on φ/128
101: Count on φ/512
110: Count on φ/2048
111: Count on φ/4096
Refresh control can be performed. When refresh control
is not performed, the refresh timer can be used as an
interval timer.
0: Refresh control is not performed
1: Refresh control is performed
This bit can be read from or written to. However, the
write value should always be 0.
Rev. 2.00, 03/04, page 99 of 534